ad populum

(appeal to popularity)

The truth of a claim is established only on the basis of its popularity and familiarity. This is the fallacy committed by many commercials. Surely you have heard of commercials implying that we should buy a certain product because the brand is the city's "favorite."

begging the question

(petito principii)

In arguing for a claim, the claim itself is already assumed in the premise. Example: "God exists because this is what the Bible says, and the Bible is reliable because it is the word of God."

complex question

A question is posed in such a way that a person, no matter what answer he/she gives to the question, will inevitably commit him/herself to some other claim, which should not be presupposed in the context in question.

equivocation

Putting forward an argument where a word changes meaning without having it pointed out. For example, some philosophers argue that all acts are selfish. Even if you strive to serve others, you are still acting selfishly because your act is just to satisfy your desire to serve others.

false dilemma

Presenting a limited set of alternatives when there are others that are worth considering in the context. Example: "Every person is either my enemy or my friend. If he/she is my enemy I should hate him/her. If he/she is my friend I should love him/her." Obviously, the conclusion is too extreme because most people are neither your enemy nor your friend.

genetic fallacy

Thinking that because X derives from Y, and Y has a certain property, X must have the same property also. Example: His father is a criminal, so he must also be up to no good."

non-sequitur

A conclusion is drawn which does not follow from the premise. This is not a specific fallacy bur a very general term for a bad argument.   

red herring

Within an argument some irrelevant issue is raised which diverts attention from the main subject. The function of the red herring is sometimes to help express a strong, biased opinion. The red herring (the irrelevant issue) serves to increase the force of the argument in a very misleading manner.

slippery slope

Arguing that if an opponent were to accept some claim C1, then he or she has to accept some other closely related claim C2, which in turn commits the opponent to a still further claim C3, eventually leading to the conclusion that the opponent is committed to something absurd or obviously unacceptable. 

This style of argumentation constitutes a fallacy only when it is inappropriate to think if one were to accept the initial claim, one must accept all the other claims. 

straw man

Attacking an opponent by attributing to him/her an implausible position that is easily defeated when this is not actually the opponent's position. 

suppressed evidence

Where there is contradicting evidence, only confirming evidence is presented.

ethos

(credibility)

convincing by the character of the author. We tend to believe people whom we respect. One of the central problems of argumentation is to project an impression to the reader that you are someone worth listening to, in other words making yourself as author into an authority on the subject of the paper, as well as someone who is likable and worthy of respect.

pathos

(emotional)

persuading by appealing to the reader's emotions. We can look at texts ranging from classic essays to contemporary advertisements to see how pathos is used to persuade. Language choice affects the audience's emotional response, and emotional appeal can effectively by used to enhance an argument.

logos

(logical)

persuading by the use of reasoning. Giving reasons is the heart of argumentation, and cannot be emphasized enough.